General Meeting Summary 4/11/13
- Radiation dose for a detector at 4 m from target at 1 uA and for a 10-cm target based on dominant background particles (note in Hamlet's report: blue=photon, red=electron, green=positron) using P. Degtiarenko simulations show:
- Highest background at smallest angles
- Sweeping magnet reduces background by orders of magnitude
- Effect of accumulated radiation dose for a PbWO4 detector located at 4m from target, at 1 uA, for a 10-cm long target
- light yield and slope do not change up to an accumulated dose of 50 kRad, i.e., experiments can run until reaches that (conservative) limit
- above 50 kRad one can use UV curing to recover the original properties of the PbWO4 blocks. Note that UV curing can be done multiple times. In run plan experiments should consider adding time for curing. Typical curing time is 1 shift, so about 8 hours.
- Note that these are very conservative estimates as they do not include additional items like shielding around the detector
- Question if similar radiation dose information was available for PbF2
- WACS will run with a radiator, so may need to schedule more curing time than other experiments. Needs to be estimated.
- Work on an instrumentation document summarizing technical details of the detector and background studies is in progress. This document will be available in LaTeX for experiment proposals to include as appendix.
- DVCS simulations done for all energies. They show that almost all settings from the DVCS kinematics table are statistically feasible except for the last two (high Q^2) settings. Effects from DVCS are small in the model used. However, this model does not describe the unpolarized DVCS cross section data, and so needs to be updated with a more realistic model.
- Work on physics motivation and presentation in progress
MAGNET DESIGN vs. ACCEPTANCE
- Discussion on choice of minimum angle magnet bore vs. acceptance (see Rolf's email)
- Proposal submission due date is Monday, 6 May, at 8 AM.
- Target date for circulating proposal drafts before 25 April.
ITEMS FOR NEXT MEETING:
- Updates from the experiment proposal preparations
- Update on instrumentation document for appendix
- Based on previous proposal(s) prepare list of requests for information on technical aspects of the detector, e.g., paragraphs, figures etc. needed for the proposal instrumentation section
NEXT MEETING: THUR, 18 APRIL at 9AM (EDT)